If you ever drive at night, there’s a good chance you’ve noticed an increasing problem with blinding headlights. In some cases, people are simply driving around with their high beams on, but that doesn’t fully explain the problem. Anyone who’s flashed their lights at an oncoming driver to let them know their high beams are on, only to get hit with their actual high beams can tell you that. One thing is for sure, though — it’s not a good thing.
Now, the regulations governing headlights haven’t changed in decades, but that doesn’t mean increased glare is all in your head. As John Bullough, the program director at the Light and Health Research Center at the Icahn School of Medicine at Mount Sinai, told Business Insider, there are three main reasons people are having a harder time seeing clearly while driving at night.
The first is probably the most commonly understood, and that’s the fact that Americans keep buying taller and taller vehicles. Add six inches of ride height, and the lights get six inches higher. The report cites a JD Power study that says about 53 percent of vehicles sold here in 2010 were trucks or SUVs, but by 2021, that number had risen to almost 79 percent.
More trucks and SUVs probably wouldn’t be as much of an issue if it weren’t for the second factor: misaligned headlights. Bullough told Insider that in a recent test, his team found that about two-thirds of the cars that were tested had at least one misaligned headlight. There’s also no regulating body in charge of making sure headlights are aligned properly. As Matt Brumbelow, a senior research engineer at the Insurance Institute for Highway Safety, told Insider, once a headlight is installed on a vehicle, “there’s no testing to make sure that it’s still aimed properly or that it’s putting out enough light on the road and it’s not glaring other drivers.”
The final factor is the color of the lights themselves. A halogen bulb’s yellow-tinged color is warmer than the bluer, white light that LEDs emit and therefore gentler on the eyes. So while a halogen and an LED headlight could be equally bright, the human eye will see the LED one as brighter and harsher. “The eye is sensitive to those blue wavelengths, but the light meter is not,” Mark Rea told Insider, a professor at the Mount Sinai Icahn School of Medicine.
The good news is, there’s a potential solution on the horizon. The National Highway Traffic Safety Administration finally made it legal last year for automakers to begin selling vehicles with adaptive driving beam headlights. Those lights continuously adjust the beam of light to avoid blinding other drivers, as well as pedestrians. But since the NHTSA’s regulations are significantly different than they are in Europe, where the technology has been legal for a while, it will likely be several years before they show up in the U.S. And even then, it will take even longer for them to become common. So things could get better eventually. It’ll just take a while.